Re: ORGLIST:Nitrogroup reduction

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From: rajkn (rajkn_51$##$sancharnet.in)
Date: Sun May 09 2004 - 10:22:24 EDT


5 or 10 % Pd-C and cyclohexene
as H donor-cum-solvent
is a mild t-BOC compatible
alternative.
Reflux follow rexn by tlc
Prof KN Rajasekharan
Unic Kerala
India
  ----- Original Message -----
  From: Maringanti Krishna
  To: everybody$##$orglist.net
  Sent: Thursday, May 06, 2004 6:19 PM
  Subject: ORGLIST:Nitrogroup reduction

  Hi All:
  I need to reduce an aromatic nitro group to -NH2. It is a large molecule and I have an Acetal and t-BOC protections elsewhere. I have tried the following methods.
  1. Raney Nickel, Hydrogenation: Several spots on TLC (after complete disappearance of starting material, and after 48 hours)
  2. Pd/C Hydrogenation...very low yield after 48 hours
  3. Pd/C hydrazine hydrate. Reaction is OK but, the yield is verylow. Difficult to get pure product. Also, acetal deprotection
  4. Electrolytic iron/ ammonium acetate and ammonium chloride. Acetal deprotection is occuring. At rt. reaction is extremely sluggish. At reflux, acetal deprotection is taking place.

  Can someone suggest an alternative method?
  Krishna

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